Comments on: Japanese Beetles: Everything you always wanted to know!

By: Joann Woy

Joann Woy — Thu, 28 Jul 2011 14:23:46 +0000

I have been keeping free-range chickens for several years and now I have virtually NO Japanese beetles, after having devastating infestations of them for over a decade. The birds scratch up and eat the grubs; they eat the mature adults. I know this isn’t the solution for everyone, but a small flock of backyard fowl works!

By: Plant Clinic

Plant Clinic — Mon, 11 Jul 2011 21:55:05 +0000

When the first group of Japanese beetles arrive, try to spray them with a strong stream of water to deter them. Once they start feeding they emit a scent that attracts other beetles. For smaller plants knock them off into a container of soapy water. Neem oil can also be applied (when temperatures are below 86 degrees to avoid burning the leaves.) The residual on the leaf will also help deter them, at least temporarily.
Next year, in May apply a soil drench of systemic imidachloprid.
Keep plants healthy, water in dry periods, mulch and fertilize with a balanced, 10-10-10 fertilizer.

By: James Huber

James Huber — Mon, 11 Jul 2011 16:31:05 +0000

we have a large Linden tree the beetles have defoliated. Should we begin a fertilizer treatment or some other treatment to help the tree?

By: Plant Clinic

Plant Clinic — Wed, 07 Jul 2010 20:11:08 +0000

You could potentially harm your plants by spraying alcohol or window cleaner on your leaves. If you insist on trying it, first spray it on a few leaves and wait a few days to see if the leaves are harmed.

By: Kathy

Kathy — Tue, 13 Oct 2009 19:16:04 +0000

The best “treatment” I have found for Japanese beetles is to keep my roses and trees as healthy as possible. In past years we have had moderate to severe rose damage. This year, on the same roses, the damage was minimal. The changes were; 1 – I kept everything mulched and watered, and fed the roses well; 2 – I removed the Virginia Creeper that was attracting large numbers of beetles to my yard; 3 – I was vigilant with the soapy water; 4 – the “tastiest” rose I have was in a pot, so I moved it off my deck (lower ground is good) and camouflaged it with other perennials that wove foliage among the rose canes; and 5 – I removed the few leaves and flowers that had been munched on. After first few weeks they stopped bothering my roses.
The extra water and mulch around my linden seemed to do the trick.

By: leslie

leslie — Thu, 27 Aug 2009 19:10:05 +0000

I have over 150 roses here in Wisconsin. I only have floribundas, gradifloras, rugosa, shrub and knock outs. This is the first year I have been invaded by japanese beetles. Because I am retired, I am able to maintain a constant and highly vigilant attack. Dropping them into soapy water kills them but so will most any liquid mixture, i.e., vinegar (soap is cheapest). This picking off of beetles is time consuming and also those that fly away return within an hour so you have to do another walkabout. They are lazy in the morning but peak from noon-5pm, and they love full sun. If it rains, they hide on the undersides of the leaves. I have found that the scent of the beetle is left on the leaf/flower and must be completely removed or beetles will return to the site and this includes any leaf/flower that has been given the “lace” treatment. I have used most every spray chemical out there, and they are only effective for about 2-4 days. Not only is this costly it is dangerously toxic to me, others and the planet. Sevin has been put on my lawns and gardens 3 times this year and we’ll only know the outcome next season (2010), and it’s also costly to treat more than an acre. (BTW: Sevin is banned in canada.)

Currently, I am researching specific companion plants that will repel the beetle…. rue(very invasive and causes skin burning), tansy (invasive), chives (invasive). I am down to garlic, sage (herb), parsley, nepta (catmint), pelargoniums (scented geraniums) and alliums. It is too late to plant now but I will be doing that for next year. I did, however, buy the sage and garlic spices in the grocery store and will be sprinkling that about when this unusual August rain stops. Japanese beetles are supposed to be gone around 8/15, but they are more prolific now because of the rains. The interesting thing about this beetle is that it is moving quickly across the country and I believe what it did not eat at all before it is now eating and enjoying! It does eat lilacs, magnolias, russian sage, viburnium, some daisy and some lillies. So please include those on the list of what they eat and are attracted to.

Any other treatments for this invasive bug ?

By: stephanie

stephanie — Sun, 16 Aug 2009 13:36:20 +0000

I live in Pa. and I just realized that I have not seen any japanese beetles around my area this year. Is this common, are there year’s when they don’t emerge or there number’s are decreased. Because by this time usually have been enjoying my garden,not missing them really just curious.

By: Nick Michaud

Nick Michaud — Sat, 08 Aug 2009 03:02:11 +0000

Is it just me, but I have noticed that Japanese Beetle die when they feed on my Pelargonium. I hope someone has observed this too and is looking into it.

By: Mitch Adamus

Mitch Adamus — Fri, 07 Aug 2009 22:22:23 +0000

For a couple years now I have been filling a squirt bottle with isopropyl alcohol and squirting the darn buggers with this.
It is labor intensive, I make the rounds every day, but if you catch them early I beleive you can prevent them from laying their eggs. I have seen no damage to any plant from the alcohol,
such as elm, hazel, rose, grape, Virginia creeper, Wisteria.
Rubbing alcohol, 71% or 91% works fine.

By: kjaros

kjaros — Thu, 30 Jul 2009 14:06:33 +0000

Interesting! The beetles are less active on my Austin roses but all over the others. I haven’t had much of a problem with them on the leaves but they burrow into the petals and – woosh – the flower’s gone in a day or less!